The present invention relates to a fixing device in use for an image forming apparatus of the electrostatic recording type, such as a copying machine, a facsimile or a printer.
A conventional image forming apparatus based on an electrophotographic system operates in the following way. A photosensitive member as an image carrying body is charged by a charger. The charged photosensitive member is irradiated with light containing image information to thereby form a latent image on the photosensitive member. The latent image is developed, with a developing device, into a toner image. The toner image is transferred onto a recording medium to form or reproduce a picture on the medium.
With colorization of the image, there is proposed a color image forming apparatus of the tandem type for forming a full color image. This type of the image forming apparatus is provided with a plurality of image forming units each executing the image forming process as mentioned above. Color toner images of cyan, magenta, and yellow, and preferably black are formed on photosensitive members provided for those colors. At transfer positions on the photosensitive members, those toner images are superimposed one on another, and transferred onto an endless intermediate transfer body.
The image forming apparatus of the toner image transfer type includes a fixing device. The fixing device contains a fixing nip part formed with a couple of rollers. The fixing nip part nips and transfers the recording medium. When the recording medium passes through the nip part, the toner image, not yet fixed, on the recording medium is fused under pressure, and is fixed on the recording medium. Since the fixing unit heats the toner for its fusing, temperature of the rollers is high.
For example, it has proposed in JP-A-2001-249562.
When the fixing device is detached from the image forming apparatus immediately after the printing operation ends, a message to inhibit the worker from touching the hot rollers is visually presented for the purpose of jamming removal or part replacement.
However, it is inevitable that the worker will touch the hot rollers carelessly or accidentally. Accordingly, use of only the message is not sufficient for giving a sure warning to the worker.